We have been successful in preparing several highly purified forms of cytochrome P-450 and in examining their magnetic ciruclar dichroism spectra. The main advantages of the method lies in spin-state analysis of the oxidized form. We will continue these studies on P-450 by examining them in reconstituted synthetic membrane like systems. In addition, we will carry out studies on the perturbations of the MCD spectra of ligated hemoglobins which are caused by the allosteric effector, inositol hexaphosphate.